Embodiments relate to epoxy resin additives for use in subterranean operations and, more particularly, to napthol-based epoxy resin additives for use with resin compositions and resin-cement composites as well as methods of using the resin additives in well cementing operations for subterranean formations.
In well operations, such as well construction and remedial cementing, cement compositions are commonly utilized. Cement compositions may be used in primary cementing operations whereby pipe strings, such as casing and liners, are cemented in wellbores. In a typical primary cementing operation, a cement composition may be pumped into an annulus between the exterior surface of the pipe string disposed therein and the walls of the wellbore (or a larger conduit in the wellbore). The cement composition may set in the annular space, thereby forming an annular sheath of hardened, substantially impermeable material (i.e., a cement sheath) that may support and position the pipe string in the wellbore and may bond the exterior surface of the pipe string to the wellbore walls (or the larger conduit). Amongst other things, the cement sheath surrounding the pipe string should function to prevent the migration of fluids in the annulus, as well as protect the pipe string from corrosion. Cement compositions also may be used in remedial cementing methods, such as in squeeze cementing for sealing voids in a pipe string, cement sheath, gravel pack, subterranean formation, and the like. Cement compositions may also be used in surface applications, for example, construction cementing.
Other types of compositions, including non-cementitious settable sealant compositions, such as resin-based sealants, may be used in the primary and/or remedial cementing operations described above. These compositions may be circulated through the well bore for use in any of the primary or remedial cementing operations used in the field. Additionally, resin compositions may be blended with traditional cement compositions to create resin-cement composites which may also be used in any type of primary or remedial cementing operation. Amongst the many uses for resins, applications in the oil and gas industry are unique in their demand for long resin pot life and controlled density.
It is well known that resins used in well cementing may only be used in formations where the bottomhole static temperature is lower than the glass transition temperature. For example, if resin compositions are deployed in formations where the bottomhole static temperature is greater than the glass transition temperature of the resin, the cured resin may have reduced compressive strength and decreased durability. Therefore, it may be difficult to use resin compositions in every operation site in which they may be desirable.
Resin fortifiers, such as methylenebisphosphonates are one attempted solution to this issue. However, the resin fortifiers may not form covalent bonds with the resin and thus their effectiveness may decrease over time. Another attempted solution is the use of epoxy resins with more than two epoxy groups. These resins form a denser epoxy network as compared to resins with two or less epoxy groups, however, they may also have high viscosities and short thickening times. As such, they may not be able to be successfully placed into subterranean formations.